Pneumatic metal straightener



Feb. 28, 1939. F. J. HAUSCHILD v I PNEUMATIC METAL STRAIGHTENER Original Filed Dec. 51, 1934 2 Sheets-Sheet 1 ITJ/fazamachild @2 53). m'vflpw GUM Feb. 28, 1939.

F. J. HAUSCHILD PNEUMATIC METAL STRAIGHTENER Original Filed Dec. 31, 1934 2 Sheets-Sheet 2 1 Ill/I221 Kim; a h

ild

Patented Feb. 28, 1939 PNEUMATIC METAL STRAIGHTENER Frederick J. Hauschild, Oneonta, N. Y.

Application December 31, 1934, Serial No. 759,984 Renewed April 14, 1937 16 Claims.

This invention relates to devices for flattening out or straightening out sheet metal and particularly to devices for bringing back, to its normal condition, sheet metal parts of automobiles which may have been crumpled, bent or dented as by collision and the present application is dcontinuation in part ,of the application for patent, filed February 16, 1933, Serial No. 657,123.

It is common in straightening or flattening out fenders and like sheet metal work for the fender to be manually hammered back into shape but while this secures a general flattening out of the crumpled or dented portion, it substitutes for one very high dent or wrinkle a series of small dents 15 or facets and the metal is never absolutely flattened so that it looks like new.

Another device for this purpose, and most generally used, includes two opposed rollers carried by a frame, which rollers are disposed on opposite sides of the sheet metal and then the crumpled or dented sheet metal is ironed out by these rollers. This device is unsatisfactory for heavy sheet metal or for anything except small and shallow dents because it requires the application 25 01' considerable strength in order to operate it and can only be operated manually. The stiffer the sheet, the more difllcult it is to iron the wrinkle or dent out by this mechanism.

Another means attempted to be used for this purpose includes an electrically or mechanically operated hammer opposed to a dolly or anvil, In this case, the hammer is urged by a spring against the metal and retracted by a motor operated cam. This construction is impractical for the reason that the spring cannot be made strong enough to exert the requisite impact on the sheet metal. Furthermore, devices of this same general nature have never been provided with a support or guideresting upon the sheet metal i self and supporting the hammer in proper spaced relation to the sheet metal. As a consequence, the workman has been obliged to support the frame of the machine at the requisite distance and this requires a very great amount of strength and energy on the part of the workman. Furthermore, devices of this character, not provided with a supporting guide, must be held with the axis of the hammer or impact member exactly atright angles to the face of the sheet or otherwise a dent will be formed in the sheet metal rather than the dent removed as the hammer will strike obliquely down-jagainst the sheet metal. Furthermore,-

.unless devices or. this character having no supporting guide are held in exactly the right posi- 55 tion, which holding must be accomplished by main strength on the part of the workman, the hammer will be either too far away from the work to exert the proper impact or it will be too close to the work and will be likely to cause a reverse dent to be formed. 5

The general object of my invention is to provide a sheet metal flattening machine or straightener which is easily handled, which is applicable to a large range of work, which may be used not only for taking the dents and wrinkles out of fenders 10 and like parts but can also be applied to the doors and sheet metal bodies of cars and which eliminates the exertion of great muscular effort and strength on the part of the operator.

A further object is to provide a mechanism of this character in which a pneumatic hammer is used to cause the projection of a ram whereby an elastic stroke is secured whose amplitude depends on the height of the dent or wrinkle and to provide in connection with the pneumatic hammer a supporting guide carried on or formed with the casing of the hammer open at its lower end and having an internal diameter larger than. the ram and whose open lower end rests on the sheet metal and supports the hammer casing thereon with the rain at a predetermined distance from the sheet metal when the ram is retracted.

A further object is to so form this supporting guide that the hammer casing will not be tilted with reference to the sheet metal but will be naturally supported in a position perpendicular to the plane of the work. I

A further object is to provide means to support the sheet metal substantially all around the "dolly and the ram so that the metal may be hammered 5 down tothe plane of the support.

Myinvention is illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation of the tool;

Figure 2 is a longitudinal section through the 40 hammer, dolly, and the upper and lower portions of the yoke or handle;

Figure 3 is a like section of the hammer and dolly showing the ram running downward;

Figure 4 is a fragmentary section of lower por- 5 tion of the hammer and a sector-shaped bell or guide;

Figure 5 is a bottom plan view 01 the parts shown in Figure 4.

- In the drawings, 10 designates an approximate- 1y .U-shaped yoke or handle and II a split clamp having a socket l2 into which the upper end of the yoke is inserted. A bolt l3 holds the clamp in clamping position. The lower end of the yoke is inserted in a socket M which carries or is u .to jam the nuts and lock them in place.

formed with a sleeve l5. 2 The ends of the yoke or handle may be held inthe sockets l2 and I! in any desired way and either detachably or by welding or brazing.

Extending upward loosely through the sleeve is a screw-threaded rod l8 carrying the knurled nuts I! and i8 above and below the sleeve i5 and bearing against,the spring washers l9 which act The lower end of screw it has a wing it and its upper end has a spherical head 20 carrying the dolly 20, constituting an anvil.

Carried within the clamp H is the cylindrical body 2| of a pneumatic hammer of any suitable type or make. Reciprocating within the body is the hammer or piston 22 having a head 23 projecting from its lower end. The hammer is limited in its downward movement by any desired means as by striking the bottom of the chamber 24 within which the hammer reciprocates. The lower end of the hammer body M has a relatively small bore 25, within which the head 23 operates, and this bore is enlarged toward -the.

lower end to receive the bushing 26. Within this bushing is disposed the shank 210i 2, ram, the head of which is designated 28. The body 2| is reduced in diameter at its lower end and surrounding this reduced portion is a coiled retractile spring 29, the upper convolution of which is engaged-in a groove in the reduced portion of the body, the lower convolution being engaged in groove 28 formed in the head 28 of the ram. This spring urges the ram upward into sleeve 26, the upper end seating against a shoulder 30 on the sleeve 26.

Surroundng the body 2| is a split collar 3! held clamped in the body by a bolt 32. This collar constitutes a stop for an element 33, which constitutes a guide and hammer support. The upper portion of this element 33 is tubular and snugly flts on the body 2| while the lower portion isflared. outward at 34 like a bell, as shown in Figure 1. but in Figures 4 and 5 the bell-shaped portion of the guiding and supporting element is not a complete circle, but has a lateral face, which is tangential, to the head 28. The bell-shaped portion 34 or 34 is preferably cut out at 3% to lighten it. The hammerbody 2| and piston 22 are shown as constructed in accordance with Patent No. 711,859, granted October 21, 1902, to W. M. Holden and, therefore, I have not attempted to show the pneumatic tool in detail. It is 'to be distinctly understood, however, that other forms of pneumatic hammer may be used.

While I have illustrated the yoke or frame III as being of one piece, yet it is obvious it might be formed 01' several pieces and while I have illustrated it as being approximately C-shaped, it may be otherwise, formed to embrace the work en? hold the dolly and hammer in opposed reat on.

Compressed air or, if the'hammer be a steam" hammer, steam may be admitted to the hammer body above the piston 22 through the flexible pipe 31. This is connected to the inlet pipe 38 and flow of air is controlled, preferably, by afoot valve not shown, resting on the floor and operated by the foot.

In using this machine, the bell-shaped support.

34 is rested flat on the fender or other work to be flattened, then the nuts I! and I8 are loosened and the dolly brought up against the under face of thework, whereupon the nuts I1 and I8 are tightened against the split locking washers l9,

In Figure 1 this bell is circular in plan,

and the dolly held rigidly inposition. Under" moves downward after the hammer stops or reaches its lowermost position, leaves the hammer, as shown in Figure 3, and strikes a blow against the sheet metal. The hammer descends until its force is expended and then returns to the position in Figure 2, under'the action of the spring 29. I v

The collar 3 l is preferably provided with means detachably holding the element 33 in place against dropping off. For this purpose, I use a spring finger 38, which is attached to the collar 3i and adjacent its extremity a tooth 4| engaging in a circular groove 42 in the element 33. This construction permits the element 33 with its bell-shaped portion 34 (or 34) to rotate freely around the hammer body 21 and over the work. This adds to the ease with which thisimplement may be manipulated over the work and permits the half bell 34 to follow along a bead a on the work A, which bead may have a curvature in its length which the end face of the bell must for use on the beaded edge of a fender or in proximity to the bead which extends along a car body or across a car door.

By using a ram or impact member 21-28 and not striking the work directly by the hammer 22, I secure a blow which is akin to the blow given by a hand hammeri This is much superior to the solid, unyielding blow given -by mechanically or electrically operated hammers or which would be given by a pneumatic, directly operating hammerr Thus the stroke of my ram is elastic and yet has a strength and power. much greater than can be-secured by the use of a spring. Thus the hammer will gradually work down a protuberance or flatten out an irregular surface gradually whereas if the hammer is operated mechanically with the same stroke'at all times, either the protuberance or irregularity would be mashed down at one stroke or some part of the mechanism would have to break.

A further advantage of my mechanism resides in the provision of this supporting guide, that is,

ram when the latter is retracted. The ram has a stroke of approximatelyiy ths of an inch and the bell, constituting the support and guide, holds the work this distance from the hammer when the hammer is retracted, thus allowing a full play of the hammer and preventing the work from being crowded up against the hammer itself which might occur' if the hell were not used.

Not only does the bell act as a gage'preventing the work from being brought closer to the extremity of the impact member than %ths of an inch but it also acts as a support for the frame,

' which the bell will act as aguide preventing tllt- I arcane and forth over the work until'the irregularity is entirely ironed out or hammered out.

Still another function of the bell, which it will be notedforms an extension of the hammer casing or cylinder, is that it naturally supports the hammer casing" at right angles to. the surface of the work. The larger the mouth of the bell, the more-perfectly does this bell act to support the hammer at right angles to the work and impede any slight tilting movement of the hammer with relation to the work. If there is no extension of the hammercylinder or casing below the hammer and extending more or less around the hammer so that this extension will rest upon the work, then the operator would have to take, great care to holdthe hammer cylinder always in a vertical positio'n'or at' right angles to the work. In view ofthe 'weight'of the frame and parts thereof, and,

if there was no support for the hammer cylinder or frame Ill, the operators arms would quickly weary and with the slightest inattention, the

frame would be tilted, causing the hammer to strike an oblique blow against the metal and the stead of getting out the old 'dent or irregularity. The guide or supportconstituted by the bell on the lower end of the cylinder slips easily over the face of the sheet metal while it acts as a support for the frame and allied parts. The weight being off the operatives arms, the. operator can readily slide the device in all directions over the dented orcrumpled portion with great ease and with no particular attention except to see whether or not the surface has been brought down evenly and every ridge flattened out. Furthermore, and most importantly, by supporting the hammer on the work, vibration is not transmittedto the operators hands and arms. I

In this mechanism, of course, the dolly crowds the dents upward from the bottom while the hammer sets the crimps or kinks downward level with the dolly, thus leavin a flatsurface. The shape of the dolly depends upon the shape of the metal to. be straightened and the dolly may be readily removed and a new dolly put in place I whenever it is necessary to change the shape of the dolly.

"Though I have illustrated the bell as'being engaged with the body of the hammer casing by the collar 3i and spring 40, yet other means of engagement might be used and yet secure the adiustment which is desirable and necessary,

While I have lllustratedthe supporting and u ding lower end relative to the hammer, yet I do not wish tobe limited in this matter as obviously-the bell might be madeof smaller diameter and yet function as a support for the hammer cylinder and the' frame-and rthus achieve particularly the functions of my belle The larger the bell is in diameter, however, the greater the extent to ing of the hammer casing, hammer" and'dolly with relation to the work. a, t The machine inactual practice makes about 7000 strokes per minute. It is to be understood thatthe bell is not initially-placed directly over 'the'dents to be flattened but-the machine works bell as having a large diameter at its dent. At 7000 strokes per minute the ram has no time to spring back the full three-eighths of an inch, andas a consequence the ram and dolly exert more of a vibrating or pressing action on the dented metal which prevents the metal from stretching. This is particularly important in metal straightening. When the machine is dragged over the dented or deformed surface,

strain is placed on yoke ill, but .because this yoke has some inherent springiness, the yoke will resiliently spread under this strain and the bell can climb over the dents.

. I claim:

1. A sheet metal flattener includin a casing, a hammer therein, and an impact element separate from the hammer and adapted to be struck by the hammer, a dolly, means for holding the casing and dolly in opposed relation, the casing having a longitudinally rigid downwardly flared extension extending downward and outward below the hammer a distance approximately equal to the stroke'of the impact element and adapted to contact with the work and support the casing a predetermined distance from the work and from lateral tilting movement, the free extremity of the extension being spaced'frcm the impact element a substantial distance whereby to support the casing at afixed distance from the work, at right angles thereto and against tipping movement.

2. A mechanism for flattening sheet metal ineluding a substantially U-shaped frame, a member carried upon one end of the frame and supporting a dolly, a hammer body carried upon the other end of the frame in axial alinement with the dolly, the hammer body and the dolly being relatively adjustable toward or from each other, a hammer therein, an impact member separate from the hammer disposed within the body and adapted to be struck by the hammer, and a bellshaped, rigidextension on the casing of the hammer extending toward the dolly and concentric therewith, the lower edge of said extension be- 'or from each other, a hammer within the body,

a ram carried by the lower end of the body, struck by the hammer, and impelled outward free from the hammer, means for retracting the ram into its initial position when the force of the blow has been spent, and a work-engaging element, carried by the body, and at its lower end flaring outward in substantial spaced relation to the ram whereby to provide a large area of support for the casing upon the work and to resist tipping movement. I

4'. A sheet'metal flattener including a yoke, a dolly carried at one end of the yoke, a pneumatic hammer body 'carried on the other end of the yoke and axially opposed to the dolly, a hammer within the body, the hammer body and the dolly being relatively adjustable toward or from each other, a ram carried by the lower end of the body, struck by the hammer, and impelled outward free from the hammer, means for retracting the ram into its initial position when the force of the blow has been spent, and a workall engaging element carried by and fitting around the body and freely rotatable thereon, and at its lower end flaring outward and downward with the inside face of its lower portion in substantial spaced relation to the ram whereby to afford a large area of support for the casing on the work and prevent tipping movment of the casing.

5. A sheet metal flattener including a yoke, a dolly carried at one end of the yoke, a pneumatic hammer body carried on the other end of the yoke and axially opposed to the dolly, a hammer within the body, the dolly and the hammer body being relatively adjustable toward or from each other,'a ram carried by the lower end of the body, struck by the hammer, and impelled.

outward free from the hammer, means for retracting the ram into its initial position when the force of the blow has been spent, and a workengaging element, carried by the body, and at its lower end flaring outward and down in substantial spaced relation to the ram, the element being adjustable longitudinally on the body.

6. A sheet metal flattener including a yoke, a dolly carried at one end of the yoke, a pneu- ,m'atic hammer body carried on the other end of the yoke andaxially opposed to the. dolly, the hammer body and the dolly being relatively'adjustable toward or from each other, a hammer within the body, a ram carried by the lower end of the body, struck by the hammer, and impelled outward free from the hammer, means for retracting the ram into its initial position when the force of the blow has beenspent, a workengaging element, carried by the body, and at its lower end flaring outward and downward into substantial spaced relation to the ram to afford a relatively large area of support for the casing upon the work, the element at its upper portion surrounding the body, and a collar adjustably engaging the body and constituting a stop against which the element engages,

' 7. A sheet metal flattener including a yoke, a dolly carried at one end of the yoke, a pneumatic hammer body carried on the other end of the yoke and axially opposed to the dolly, the hammer body and the dolly being relatively adjustable toward or from each other,'a hammerwithin the body, a ram carried by the lower end of the body, struck by the hammer, and impelled outward free from the hammer, means for 'retracting the ram into its initial position when the force of the blow has been spent, a workengagin element, carried by-the body, and at its lower end flaring outward and downward into substantial spaced relation to the ram whereby to afford a large area of support for the casing, the element at its upper portion surrounding the body, and a collar adjustably engaging the body and constituting a stop against which the element engages, said collar having a resilient finger engaging an annular groove in the element.

8. A sheet metal fiattener including a dolly, a fluid operated hammer opposed to the dolly and including a casin and an impact member within the casing, and a sheet metal engaging element constituting a support for the hammer upon the work and forming a longitudinally rigid downwardly expanding extensionof the casing at its lower end, the diameter of the. extension at its lower end being substantially greater than the diameter of the hammer casing and extending a substantial distance around the axis of the casing, said extension at its lower end being spacedl from the impact member when the iatter is projected against the work and aflording a wide sup-' port for the casing against the work and impeding any tilting movement of the casing relative to the work.

9. A sheet metal flattener including a casing, a

radially outward and downward beyond the hammer impact element a distance equal to the stroke thereof and adapted to contact with the work and support the hammer casing at a fixed distance from the work, the free extremity of the extension substantially surrounding the impact element when the latteris projected against the work, said-extension at its lower end having its inner face spaced from the impact element when the latter is projected against the work a distance such as to aflord a relatively wide support for the casing against the work and impeding any tilting movement of the casing;

10. A mechanism for flattening distorted sheet metal including a substantially U-shaped frame,

a member carried upon one end of the frame and supporting a dolly, a fluid operated hammer body carried upon the other end ofthe frame in axial alinement with the dolly, the hammer body and dolly being mounted for relative adjustment toward or from each other,a hammer therein, an

impact member disposed within the body and' adapted tobe struck by the hammer, and a bellshaped rigid extension on the lower end of the casing of the hammer extending toward the dolly and concentric therewith, the lower edge of said extension being disposed in a plane spaced from the retracted position of the impact member a distance equal to the'stroke of the impact memv her, the lower end of the bell-shaped extension being spaced radially a substantial distance from the impact member when the latter is projected and affording a relatively wide support for the casing upon the work and impeding any tilting movement of the casing.

11. A sheet metal flattener including a yoke, a dollycarried on one end of the yoke, a pneumatic hammer body carried'on the other end of the yoke and axially opposed to the dolly, a hammer within the body, a ram carried by the lower end of the body struck by the hammer and impelled outward free from the hammer and a work engaging element carried by the body, the lower end 'of the work engaging element having the form of a segment of a circle, the work engaging element at its lower end flaring outward laterally and rearwardly with relation to the hammer and in substantial spaced relation tothe ram whereby to provide a large area of support for the body upon the work and resist lateral tipping movement, the. work engaging element being cut away on its front face whereby its forward edge may be applied against a rib' on the metal to be flattened and may beguided along this rib with the ram closely approximating the rib.

12. A sheet metal fiattener including a yoke, a dolly carried on one end of'the yoke, a pneumatic hammer body carried on the other end of the yoke and axially opposed to the dolly, a hammer within the body, a ram carried by the lower end of the body struck by the hammer and impelled,

outward free from the hammer, a work engaging element swivelled upon the lower end of the body for free rotational movement concentric thereto,

the lower endof the work engaging element hav- 7" or ing the form of a segment, of a circle. the engaging element at its lower end flaring outward laterally and rearwardly with relation to the hammet and in substantial spaced relation to the ram whereby to provide a large area of support for the My upon the work and resist lateral tipping movement, the work engaging element being cut away on its front face whereby'its forward edge may be applied'against a rib on the metal to be vide alarge area of support for the hammer body upon the work and to -ment.

flattened and may be guided along this rib with the ram closely approximating the rib.

13. A sheet metal flattener including a pneumatic hammer having a body, a member in which the hammer body is supported for vertical adjustment; means for clamping the hammer in said supporting member against movement after ad- Justment, a'work engaging element carried by and extending downward from the lower end of the body and at its lower end extending outward in a plurality of radial directions in substantially spaced relation to the hammer whereby to proresist tipping move- 14. A metal flattener of the character described, including a pneumatic hammer body, a member in which the hammer body is supported,'a work engaging member carried by the hammer body and extending below the same and extending outward in a plurality of radial directions from the hammer body, the lower edge of the work engaging member being disposed in substantially spaced relation to the hammer operating within said body whereby to provide a large area of supwork.

operating means to the other arm, and a work engaging element adiustably carried by the operating means and extending downwardly from the operating means, and at its lower end extending outwardly in a plurality of radial directions in spaced relation to'the hammer to support the device upon the work.

16. A sheet metal flattener, including a sub stantially U-shaped resiliently yieldable yoke, a hammer casing mounted on one arm of the yoke for adjustment toward and from the other arm of the yoke, means for clamping the casing in ad+ justed position in the yoke, an impact member disposed within the casing and extending below the same, a freely rotatable work engaging element carried by the hammer casing and normally projecting'below the lower'end of the impact ele-' ment and adjustable longitudinallyofthe hammer casing, and a dolly carried on' the other arm of the yoke :and confronting the work engaging element.

mmnmcx J. Ransom. v 

